Air washer and sterilizer



Sept. 3, 1935. G. F.LINDE AIR WASHER AND STERILIZER Original Filed June 4, 1934 R06 lt/5mm@ Lim/die,

r anni A Patented Sept. 3, 1935 UNITED STATES ATENT @FFME Am WASHER AND sTEmLizsR Gustave F. Linde, Madison, Wis., assigner to Scanlan-Morris Company, Madison, Wis., a corporation of Wisconsin 3 claims. (o1. zei-123) This invention relates to the art of air washing devices, and is a division of an application filed by me on the fourth day of June, 1934, Serial No. 728,847, now Patent No. 1,998,679 dated 5 April 2S, i935, for improvements in liquid sterilizers.

In the aforesaid application I have disclosed a device for use in hospitals and bacteriological laboratories for sterilizing liquids in a tank by the lo application of heat to raise the liquid to a sterilizing temperature, said application including means for sterilizing the usual gauge glass and also a device for washing and sterilizing the air that enters the tank as the sterilized water is drawn olf. It is this latter device that forms the subject matter of the present application; and, although it is capable of useful employment in other situations than as an adjunct of a liquid sterilizer, it has been designed mainly for that purpose, and I have accordingly, in the accompanying drawing illustrated it in association with a liquid sterilizer in order that its function, mode of operation, and utility in connection with a liquid sterilizer may be better understood.

Referring to the drawing:

Fig. 1 is a vertical sectional view of the liquid sterilizer of my aforesaid application, showing the air washer and sterilizer associated therewith and forming a part thereof.

Fig. 2 is an enlarged sectional detail of the air washer and sterilizer, showing its condition when steam from the sterilizing tank is discharging therethrough.

Fig. 3 is a similar view of the air washer and 5 sterilizer, showing its condition when steam is being condensed in the sterilizing tank, or the sterilized water is being drawn therefrom, or both, and vair is being admitted through vthe washer and sterilizer to the sterilizing tank under in() the vacuum pull in the latter.

Fig. 4 is a plan section, on line 4--4 of Fig. 1, of a sanitary air gap fitting at the lower end of the system through which the incoming air is admitted to the ,air washer and sterilizer.

Fig. 5 is a sectional detail on the line 5 5 of Fig. 1.

Referring to the drawing, I0 designates a tank adapted to contain a body of water or other liquid to be sterilized, the liquid being heated by any suitable means such, for instance, as a steam coil II. From the center of the concave bottom wall I0 of the tank I0 a valve-controlled drain pipe I2 leads into a waste fitting I3, the lower end of which communicates by a short pipe section I4 and elbow I5 with a drain pipe I6 leading to the sewer. The purpose of the last described parts, is, of course, to drain olf, from time to time, any sediment that may accumulate in the bottom of the tank IIJ.

In one side of the tank Ill are m-ounted upper and lower standard gauge glass fittings Il .and I8 equipped with manually operated valves I9 and 20, respectively, which are normally open and closed only in an emergency such as the breaking of the gauge glass, and between these fittings is mounted the gauge glass 2|. Within the gauge glass 2l and coaxial therewith is the upper section of a steam pipe 22, the lower end of which upper section may be mounted in the axially bored lower plug Z3 of the fitting i8, the lower portion of the upper section of pipe 22 being bent laterally to clear the needle valve 2U, as shown in Fig. 5.

The upper end of the upperA section of steam pipe 22 communicates freely with the chamber of the upper gauge fitting Il so that it is in free communication with the interior of the upper portion of the tank I. The upper end of the lower section of pipe 22 is mounted in the plug 23 and its lower end connects into a thermostatic steam trap 24 of the well known type wherein a bellows diaphragm 25, that is expansible by the heat of the steam, carries a valve 2: cooperating with a valve seat 2l' in the bottom of the trap so that, shortly after the steam enters the ,n.1

trap the valve 2S is closed on its seat by the diaphragm 25 so as to prevent further escape of steam.

Connected into the lower end of the steam trap 24 is the air washer and sterilizer, the structural details of which are best illustrated in Figs. 2 and 3, and comprise an outer steam and air tight casing 28 closed at its upper and lower end by headers 29 and 3S, an inner tube 3l secured at its open upper end in the header 2Q, and an outer tube 32 encircling the inner tube 3l, open at its upper end, and at its lower end closed by a cap 33 in which the lower end of the inner tube 3l is seated and sealed. The upper header 2i) of the washer and sterilizer is equipped with a threaded nipple 3f: that screws into the lower end of the steam trap 2d, and in the lower portion of the inner tube BI is a ring of holes 35 that may be covered with screens B where, as is preferable, the inner tube 3| is supplied with a body of glass or porcelain beads 3l, which are used to break up bubbles in the air that is passing through the body of water in the tube 3l.

`'Ihe lower header 30 of the air washer and sterilizer is formed with a tapped nipple 38 to receive a pipe 39 that communicates with the drain pipe I2 through a T-tting 4I) in the latter.

The sanitary air gap drain fitting I3, which is preferably employed, is a hollow inverted pearshaped structure tapped to receive the threaded lower end of the drain pipe I2, and formed in one side thereof with a substantially semi-circular air inlet opening 4I, which straddles an internal baffle i2 mounted in the upper end of the tting, the baille 42 having a biased open side 42 remote from the air gap or inlet 4I, so that sediment deposited from the pipe l2 cannot splash on and thus foul or obstruct the air gap or mouth 4 I.

Brieny describing a cycle of operation, the tank Il] is nlled in the conventional manner and steam turned on to sterilize the water. The air above the water is expanded by the heat and escapes through tube 22 in the gauge glass, through the thermostatic trap 24 and through the washer and sterilizer 28 to the sanitary air gap fitting I3 which is open to the air through the opening 4I. This air in its escape depresses the liquid level in the inner tube 3| down to the holes 35, causing a partial overow of the water in the Washer and sterilizer, as shown in Fig. 2. During the sterilizing period the thermostatic trap is intermittently draining steam condensate into the inner tube 3l, replenishing the condensate blown off by the air. At the end of the sterilizing period, when the steam is turned 01T, and the water in the tank begins to cool, stopping the ow of steam through the pipe 22, the natural radiation of the thermostatic trapwill cool the expanding element in the trap, causing the trap valve to open, allowing air to flow into the sterilizer tank as the steam condenses or water is drawn therefrom. When air flows through the washer and sterilizer due to reduced pressure in the sterilizing tank, the atmospheric pressure will cause the liquid level to be lowered between the inner and outer tubes and to the level of the holes 35 in the inner tube. This, of course, raises the liquid level in the inner tube, as is shown in Fig. 3. After the level between the inner and outer tubes has been lowered to the holes 35, air enters through the holes and bubbles up through the liquid column washing and sterilizing the air. The liquid in the inner tube 3| forms an effective seal against unltered air entering the sterilizer tank, since the air can enter the tank only through the body of water in the tube 3I. When steam is formed in the sterilizer, a considerable quantity thereof flows through the system before the diaphragm in the thermostatic trap expands sufficiently to close the trap; and this steam Howing through the washer and: sterilizer sterilizes it effectively. After the trap closes, the steam condensate drains into the washer and sterilizer as previously described.

The described device not only washes the incoming air but also sterilizes it for this reason. Pure air carries no bacteria, but most air is more or less dust laden, and the bacteria are found in the dust. Hence, since the device washes out the dust, it also eliminates the bacteria and thus renders the air sterile.

I claim:

1. As an adjunct for a liquid sterilizing tank, a device for washing and sterilizing the air'that enters the tank as the water is drawn off and adapted to be sterilized by steam discharged therethrough from said tank, comprising a casing having top and bottom closures, said top closure having an air outilow duct for communication with a pipe leading into said tank and said bottom closure having an air inflow duct, an inner tube within said casing closed at its upper end by said top closure and communicating with the air outflow duct thereof, said inner tube formed with holes near its lower end, an outer tube encircling said inner tube with clearance and approximately the full length of said inner tube and open at its upper end below said top closure, and a closure for the lower ends of said tubes andthe annular clearance space therebetween above and spaced from said bottom closure. l A

2. As an adjunct for a liquid sterilizing tank, a device for washing and sterilizing the air that enters the tank as the water is drawn oir and adapted to be sterilized by steam discharged therethrough from said tank, comprising a' casing, top and bottom headers closing the upper and lower ends of said casing, said top header having a central air outilow'duct for communication with a pipe leading into said tank and said bottom header having a central air inflow duct, an inner tube within and coaxial with said casing closed at its upper end by said top header and communicating with the air loutflow duct thereof, said inner tube formed witha row of holes near its lower end, an outertube coaxial with and encircling said innerk tube with clearance and approximately the full length of said inner tube and open at its upper end below said top header, a common closure for the lower ends of said tubes and the annular clearance space therebetween above and spaced from said lower header, and a body of bubble dividing material in the lower portion of said inner tube covering said holes. y

3. As an adjunct fora-liquid sterilizing tank, a device for washing and sterilizing the air that enters the tank as'the water is drawn off and adapted to be sterilized by steam discharged therethrough from said tank, comprising. a casing, top and bottom headers closing the upper and lower ends of said casing, saidV top header having an air outflow duct for communication with a pipe leading into said tank and said bottom closure having an airinflow duct, aninner tube within said casing closed at its upper end by said top header and communicating with the air outow duct thereof, said inner tube formed with holes near its lower end, an outer tube encircling said inner tube with clearance and open at its upper end below said header, the length of each of said tubes being greater than its diameter, and a closure for the lower ends of said tubes and the annular clearance space therebetween.

GUsTAvE F. LINDE,l 

